Carbureter.



W. W. MUIR.

CARBURETER,

APPLICMION HLED MAR.I8,1914.

1,143,986. Patented June 22, 191.5.

3 sfiEETS SHEET 1.

WM/mews) 23 MW W W. W. MUIR.

CARBURETER.

APPLICATION FILED MAR. 18, i914.

6 5 w. W U W M wm a m n M TJW. d5 63 P iv 3 Di W. W. MUIR.

CARBURETER,

APPLICATION FILED MAR,I21,!':H4

l 143,986. Patented June 22, 1915.

a SHEETSMSHEET 3. -53 27 a I WELLINGTON W. MUIR, OF BALTIMORE, MARYLAND.

CABBURETER.

Specification of Letters Patent.

Patented June 1915.

Application filed March 18, 1914. Serial No. 925.476.

T 0 all wliom it may con cern Be it known that I, VVELLINGTON \V MUIR, a citlzen of the United States ot- America,

residing at Baltimore, State of Maryland,

have invented certain new and useful 1mprovemcnts in Carbureters, of which the following is a specification.

This invention relatesito carbureters and particularly to a carburetor ofthe float feed straight tube-type having no moving parts aside from the float regulated supply valve and the throttle. Uarbureters of this general type are not broadly new, as mixing devices composed entirely of static members have been known to the art from the earliest stages of its development; but in the use of these carbureters various ditficulties have been encountered. Of these diliiculties the principal one is that the richness of the mixture increases .with the speed so that with a fuel nozzle and a head of fuel sufficient to supply the engine at low and medium speeds, economical and efficient running at high speeds cannot be had, because with the increased vacuum, the supply of fuel increases out of proportion to the requirements of the engine. As the mixture becomes too rich, there is a loss not only of economy and efficiency as to the fuel consumptiom but the efficiency of the engine in point of power developed is also reduced. in the carburetor of the present invention this difficulty is overcome, in the first instance by so arranging the fuel feed that at high speeds instead ofpure gasolene or other liquid hydrocarbon being supplied to the aspiratin nozzle an emulsion of gasolene and air is ted, and, second, as the speed increases, and hence the vacuum at the nozzle and the rate of feed, the air pressure in the float chamber and hence the etfective head of the liquid fuel is decreased, so that the fuel consumption instead of being proportionate to the vacuum, thus increasing the richness of the mixture with the speed of the engine as occurred with the former carburetors of this type, is regulated, the mixture being held to the best proportions, and the quantity of fuel fed, though it increases in'aetual amount at high speeds, decreases in its ratio to the vacuum and the speed of the engine.

Another difficulty which has been encountered in practically all carburetors, is that incident to breaking upjthe gasolene, i. 6., spraying or atomizing. It is of course important that the mixture of gasolene and air should be as uniform and intimate as possible. For this purpose various xpedients have been tried, but it is difiicult to prevent the gasolene from entering the vaporizing chamber in the form of a column of liquid which is partly atomized and partly formed into globules which enter the cylinder. These comparatively large bodies of liquid are not consumed because the interior is protected by the portions near the outer surface from the action of the iiixygcn in the air and combustion is thus prevented or rendered imperfect. In this way a large amount or" gasoleru is wasted by being passed out through the exhaust and the cylinders and valves become carbonized. To overcome this difficulty in the instance of the present invention, a [uirticular type of nozzle has been provided. This consists of a coniparatirely large tube with a small exit opening or nozzle. Within this large tube and placed centrally thereof so as to leave an annular passage, is a central tube open at its lower end to the air and at its upper and registering with the nozzle opening. The outer tube is contracted at this point, there being an internalannular shoulder around the nozzle. tiasolene sfrpplied to the annular passage. The central tube being open at its lower end, forms an inlet for air entering in response to the acuum of the engine. The gasolene or other liquid fuei thus introduced is drawn up the annular passage and, turned inward radially at the nozzle, bringing it in the form. of a thin. film directly in the path of the entering air which atomizes it most completely, the spreading of the gasolcne in the form of a film and presenting it in this form being particularly effecti e in preventing the formation of globules -.\nother feature of the invention is a priming device connected to the manifold at a point between the throttle and the on gine. The primer consists of a cup open at the top connected ,to the fluid chamber by a passage leading to a nozzle at the bottom of the cup. The cup is connected to the manifold between the throttle and the engine by moms of a tube, the end of which preferably incloses the point of the nozzle at the bot tom of the cup,-leaving an annular opening around the nozzle. When the engine is turned. o er, the gasolene from the cup is being taken from the prir or or priming carbureter. Thus regulated, the engine runs at its lowest rate of speed.

The priming carbureter always acts in conjunction with the main carbureter during the running of the engine, though it is within the scope of my invention to provide means for closing the connection if so desired, and this carbureter is subjectto the regulation by reduction of the air pressure in the float chamber as hereinafter described.

When the engine gets under way, the throttle being open, the vacuum causes the aspiration of the fuel at the nozzle 9. This mixes, first, with the air entering the passage l3 and then with the air in the Vent-uri tube which enters through the air inlet 6 forming an exceedingly intimate and uniform mixture which is fed forward to the engine in the usual way. Here the second set of running conditions is in force. At this time the carbureter has the regular op eration of a constant level aspi rating carburetor. The gasolene fed to the nozzle 9 is determined by the adjustment of the valve 19, that is, by the size of the opening 17', as all the gasolcne fed to the nozzle 9 must flow through this opening at the particular pressure existing, 2'. e., the difference between the pressure at the bottom of. the float chamber and that in the Venturi tube or more particularly in the feed pipe leading to the nozzle 9.

As the speed increases. pressure in the Venturi tube, as compared to that in the float chamber, decreases, the third set of running conditions comes into effect and the carbureter operates after the third method re ferred to. With the increase of vacuum the tube 23 is emptied of fuel because of-the in creased suction and the nozzle 9 begins to draw air from the top of the float chamber through the perforations 25 via the passage 23 and the outlet 24 of the valve 19, so that the carbureting operation is shifted from the opening 10" to the opening 17, the first mixing taking place at this point. The mixture thus formed is diluted with air at the nozzle 9 and later in the venturi. In this Way the quantity of fuel fed as compared to the height of the vacuum in the venturi is reduced but the air enters the float chamher through the opening 26 in suflicient quantities to maintain the pressure on top the gasolene' so that the only reduction is accomplished by feeding a mixture of air and gasolene to the nozzle instead of pure gasolene.

As the speed increases approaching the highest rate, the fourth set of running conditions becomes effective and the rate of fuel feed as compared to the height of the vacuum, is again decreased by the reduction of the air pressure in the float chamber. This is made possible by the fact that the openings 24 and 26 are'so related that at a. predetermined speed which is near the highest for which the carburetor is adapted, the supply of air drawn from the float chamber is greater than that entering through the openings 26, and thus a vacuum is created in the float chamber and the header pres sure on the gasolene supply at this point is reduced, thus reducing the tendency of the fuel to flow to the nozzle 9. In this way the ratio of the fuel consumed to the height of the vacuum in the Venturi tube is further decreased and the existing tendency to increase the richness of the mixture is overcome.

It is thus made apparent that regulation is accomplished by the four different methods of operation of the carbureter,-the first being the lowest speed with gasolene fed through the priming carbureter only; the second being the normal low speed running of the engine with gasolene flowing in full volumeunmixed through the opening 17 to the nozzle 9. For running'underfthese conditions the carburetor is adjusted as to the size of this opening or otherwise the size of the opening 17 is determined by the quantity of gasolene required to give the most efficient running at this speed. The third method of running is with the gasolenc drawn from the passage feeding the nozzle 9 up to the poiiit where the opening 24 is uncovered. At this time mixing first takes place at 17' and subsequent dilution at the nozzle 9 and in the venturi. the deteimining elements and the elements to be determined at this speed being the size of the opening 24. The fourth set of running conditions is with the air being drawn through the opening 24 faster than it enters the float chamber through the openings 26, giving a vacuum over the gasolene in the floa-t chamber and a reduced head. The determining element under these circumstances is the relation 'of the size of opening 26 to the size of opening 94. and this opening 26 must be of such size and so related to the opening 24 that the amount of air exhausted is suflicient to create the desired vacuum over the fuel in the float chamber, and thus reduce the head so as to overcome the tendency to increase the fuel flow as related to the engine vacuum with consequent increase of the richness of the mixture.

In Figs. 5 and 6 I have illustrated my carbureter in connection with a horizontal instead of a vertical straight tube. In this instance there is a horizontal tube 40 having an air inlet 41 with a flange 42 by which it is connected to the manifold. Tn this carbun-tor the venturi 43. instead of being vertiral. lies in a horizontal position, the straight tube and vcnturi being apertured at 4-4 to admit the fuel pipe 4:3 with an in closed air pipe 46 corresponding to the 111$ niotlillm those lubm lit-lug m unted on vwtmll v :2 tunl scw'uvplug l? and lb fttl'l in a rmivt l1 loruml iulv rnl with or otl'ngrwise i-oiim-ctml to tho holly ol' lhr imtruxucut, the ol' thv or cut i-vmg' upm'l'lllml to form 2; ago Jill m-a lug to the alm'iuhu p; i "u heme-en the '-\;lll: oi the tubns "l5 and lo, Otherwise: t UH) cnrluu'otrr urn, of procisely similar Q lllhll lll'lltili illltl the parts re o'nt'1url identical that they need not be described. 1

Thu invention hus burn wt forth specifically and in clotuil in ()tllkl' that its operation um be clearly lllll'lk'lfilljllil. llowo poiz the specific tonne hm'i-in um uwll thwuriptively rather than in llwir limiting 11-iiand the svopc of the iiiwntion l5 thlini-rl in the claims.

1. in tiuulmiilti on lllhllltl iimmm n ugzm to UK i-oimwwl 1 :lullllzi d tfinl u ll Mr; hui'viiii \m,

"mums in lul he lhul r in.

a'inluriug lllfl w 's l whvu tho nu'uum in tho i ini-wnwil lwwoml :i

if. vom tuut lr-Ml fuel wl uzl {m rivlwiz' tln if inw: uvl v 11- tkilil l'zoui lllt chuuilwr to tho nozzle Mi l an air livering' air into tho 'l'iu'l par-taught tube living: in the torn: ot a hollow plug? wilw rmrulutiug thw fuel bums-l to thv nozzle.

111 a mu'bui-vtrr, :1 furl uppl chmuber, :i Mi rburvtihg puwngu. :1 furl u XZle-in the rui' uu'rliup' Hum; from llH! tiwl -H})] l V rhmnher to the nozzle un l an air tuhv taking air from tin: fuel rluimlwr o\'( the lew'el ot' the t'uol therein and (lvliwrint air into the fuel passage, the air tube being in thv toi'm ot' a hollow plug \nlm adapted to (lLlLPi'i'liflt, the capacity of tho furl uwmgr lemling from llld fuel supply to the nozzle.

ln :1 tm'lmrvter, a tuol :1 *nrburvting: pnsmge :l 'l'uol nozzle in the (-nrlmretiiu: osage. 21 tu l passage leading from the fuvl supply ahaunher to the nozzle u tllvl par= nge lending Supply chamber,

and an air u 'w taking uirt'rom the fuel vimuilwr owr the level of the fuel therein air into thv t'uul pig-rage, the in the form of u hollow plug to lltik llllll the capacity of ll im-l w1 ipr hauling: l'rom the fuel map-- :15 to (hr no: 21ml 11mins, for adjudiug h iziiii i'lllfl' to wry thtcapacity of this mwufo.

I. lo :1 warhurctvr. n l uol supply chamber, 11 (:Hlilll'ttlil; maxim; n fuel nozzle the mihurvting pflmlfl'". :2 tuel passage leading lrom tlu luv-l u iply (-luimlwr to the nozzle, lw k'UllllfilllllQ tho of the opening in lhv 1 ;l"-:lf l. llPllfi for :uljusti tho to u: x' 1h: sl/v ot' the owning who liv ng; hollow 21ml having an t n: llw bottom llllll :ils an owning:

lwcl ol tllt' l uhl, hating: :in air iulrl 0 m "l of tho l'url. flllll 11mins immiuomlo in Hi t-zlrlnuvlin; 1" k 0 luzuling twin tl l} luvi sup cr to tlzr iaozzl, :ui uh tuhv taking :u: from 1hr J puc0 in the rm rhulwh-w nlmm ll: lml lmel mill (to- 1 luwl the fuel .i :m iuhl nuopening also allow ahh '2 ol the 'l'uvl. the outlet openif the ii -r tubs and llw a r inlet opening humming inn.

imam in.

of l H luvl elmmb r l'wlutf so proportioned i 1 l sp wle the air passing: thrmg h ih wll in quantity that moving 1hr l'i'vl vii ou wr through ll opvning,

Hill n El i nt l lmuli from tho tut-l supp y 'iuimlwr to the iztfi'iltl, :ni lnlw inking air tron; th s tuvl supply hzuu w ubovo tho lr-w-l at t e fuel Him-min nil llll VPJlDQ' t in tho In. the mi'hurhtrr living; 42 it it opvrntws in three (llll'en f-H, at low :gpwul the fuel flowing ll :1 full uuinte '1 opted stream through the tun! supply to the noz le, the air tub; being filltll with QflSOlOIH to the lvvel of the l uid in ihb float chzuulmr at a. high spvellk tho gusolvno living Withdrawn from the air tube. :iir entering the. fllQl supply passage through this tube. 50 that the fuel is (lilutrct the pros ui'e on the gasoleno S. In a carbureter, a fuel supply chamber, means tending to maintain the fuel level therein constant, a carbureting passage, a fuel nozzle in the carbureting passage, a fuel passage leading from the fuel supply chamber to the nozzle and an air tube delivering air into the fuel passage, the tube being in the form of a hollow plug valve regulating the fuel supply to the nozzle, the plug valve being perforated above the level of the liquid and the fuel chamber having asmall opening only sufficient to supply a volume of air equal to the volume of fuel used at intermediate speeds. i

9. In a carburetor, a fuel supply chamber, means tending to maintain the fuel level therein constant, the chamber being closed to the entrance of air except as to an inlet of predetermined size, a carbureting passage, a fuel nozzle therein, a fuel passage leading from the fuel chamber beneath the level of the liquid to the nozzle, a plug valve for regulating said passage, the plug valve having therein an air passage leading from the air space in the fuel chamber to and into the fuel passage.

10. In a carbureter having a constant level fuel supply chamber, an aspirating nozzle, a primer consisting of a cup open at the top and having at the bottom a nozzle connected to the fuel chamber below the fuel level, a tube leading from within the cup to the engine vacuum, the" lower end of the tube inclosing the nozzle, and means for exhausting the air over the fuel. in the fuel supply chamber by way of the aspirating nozzle.

11. In a constant level carbureter having a fioat chamber, an aspirating nozzle, a fuel supply passage leading to the nozzle and an air tube normally filled with gasolene having intake openings in the float chamber above the normal level of the liquid, the air tube emptying into the fuel supply passage so that the mixing operation takes place first at the nozzle and later, as the speed and vacuum increase, is shifted to the end of the air tube, which is emptied of gaso lane at this time and serves as an air passage delivering air to the fuel passage, the float chamber having inlet openings which are sufficient to supply the air removed by the air tube at low speeds, but are insuflicient to supply the air taken at the highest speeds so that at high speed, a vacuum is created in the float chamber reducing the fuel head.

12. In a carbureter, a fuel spray nozzle, a

fuel supply passage therefor, a carbureting passage, a main fuel nozzle located in said passage, the passage being connected to the engine vacuum, a constant levelvfuel supply chamber and means for delivering air from the said chamber through the nozzle, taliing it from a point above the normal level of the liquid in that chamber, the chamber having restricted openings forthe admission of air whereby a mixture of-air and gasolene is fed to the nozzle, the restricted openings being sufiicient to maintain atmospheric pressure in the said fuel chamber at low speeds but insufiicient to supply the air taken from the fuel chamber at high speeds so that the pressure drop at the spray nozzle at increased speeds is communicated in a modified degree through the fuel supply passage to the space above the fuel in the fuel supply chamber to regulate the fuel supply to the nozzle.

Signed by me at Baltimore this 12th dayof March 1914.

WELLINGTON W. MUIR.

Viitnesses:

ZELLA K-UHN, EDWIN F. SAMUEL's. 

